1. Field of the Invention
This invention relates to a raster image processing method by a raster image processor (RIP) to render a document for example a newspaper defined in a page description language format to a content output device for example a printing device.
2. Description of the Related Art
Raster image processing methods are well-known in the graphic industry. Every document, such as a Portable Document Format (PDF) document that needs to be reproduced on a content output device such as a printer device or a display device needs to be processed to a raster graphic by a raster image processor.
It is found that in a document, used in a raster image processing method, similarity of nearby content objects is high due to the nature of the layout in the document but this similarity is not taken in account by a raster image processing method. A raster image processing method may convert these content objects with several image manipulation methods without control of the similarity between the content objects of the document. That's why today the reproduction of a document is not always correct because similar objects may be converted different so the similarity in the reproduction between the reproduced content objects is lost.
EP1883049 (FUJIFILM Corporation) discloses a raster image processing method for page description languages wherein similarity between natural images, as content objects, are checked and if similar are converted by the same image manipulation method.
If two content objects visual continues from a region of the first content object in the transition to a region of the second content object, also these content objects needs to be reproduced correctly by applying the same image manipulation methods.